Investigation of beta‐glucans binding to human/mouse dectin‐1 and associated immunomodulatory effects on two monocyte/macrophage cell lines

Abstract

Dectin-1, a specific pattern recognition receptor for β-1,3/β-1,6-glucans, is expressed mainly on phagocytes. Human dectin-1 (hDectin-1) and mouse dectin-1 (mDectin-1) were separately expressed on HEK293 cell surfaces for examination of the binding abilities of a synthetic particulate β-glucan (pβG), a product extracted from Saccharomyces cerevisiae, in this study. The binding of zymosan-FITC to hDectin-1 and mDectin-1 was inhibited by pβG at similar concentrations for 50% inhibition of binding (IC₅₀). However, the kinetics of the time course and dose response to zymosan stimulation observed for U937 and J774A.1 differed. Superoxide anion production was increased in U937 but reduced in J774A.1 when cells were treated with pβG, zymosan, or laminarin, whereas ovalbumin endocytosis was enhanced in U937 and J774A.1 treated either with pβG, zymosan, laminarin, or barley-glucan. These results indicate that the binding affinity of pβG to hDectin-1 is similar to the binding affinity to mDectin-1, and that stimulation by pβG as well as various forms of β-1,3-glucans on U937 and J774A.1 resulted in upregulation of cell activity and ovalbumin endocytosis. Additionally, other coreceptors on U937 and J774A.1 may be involved in directing different responses to superoxide anion production in these two types of cells. These results will likely contribute to further investigations on identifying the biological forms of β-glucans capable of binding its specific receptor as the effective immunomodulators.

Alternative Oxidase Mediates Pathogen Resistance in Paracoccidioides brasiliensis Infection

“…This difference could be attributed to the differential cell wall composition of conidia (mainly 1,3-beta glucans) and yeast (mainly 1,3-alpha glucans) cells. It has been demonstrated that 1,3-beta glucans are recognized by the dectin-1 receptor present in macrophages triggering cell activation, including cytokine production such as TNF-alpha [45], [46]. Additionally, our data show that the reduction in expression of PbAOX leads to a significantly increased survival rate in a mouse model of infection (Fig.…”

The Immunologically Active Oligosaccharides Isolated from Wheatgrass Modulate Monocytes via Toll-like Receptor-2 Signaling

“…Furthermore, polysaccharides/oligosaccharides with ␤-glucan structural features extracted from oats, wheat, yeasts, and mushrooms have been shown to possess immunity-enhancing behaviors (9,10). On the other hand, several receptors on immune cell surfaces have been identified as being able to recognize these carbohydrate components and process their downstream signaling (11,12). Thus, we evaluated the immunomodulatory activity and investigated the structural information of the carbohydrate components in wheatgrass.…”

Long-term Intake of Pasta Containing Barley (1–3)Beta-D-Glucan Increases Neovascularization-mediated Cardioprotection through Endothelial Upregulation of Vascular Endothelial Growth Factor and Parkin

“…As β-Glucan receptors are expressed on the surface of endothelial cells 61 , the upregulation of Parkin protein was localized in the coronary endothelial cells of P-BBG hearts. The binding affinity of dectin-1 to β-D-Glucan and its biological activity are similar in humans and mice 22 , 62 , it would thus appear that we have revealed BBG-dependent mechanisms in cultured HUVECs at rest and under acute oxidative stress. On day 7 after the exposure of HUVECs to 3% BBG, the levels of acetylated H4 histone, VEGF and MnSOD increased and were not affected by acute oxidative stress.…”